The present invention relates generally to a system for supplying a flush fluid to a semiconductor polishing machine or other apparatus. More particularly, the invention relates to a system for flowing de-ionized (DI) water through an apparatus to prevent slurry from clogging the apparatus and/or to prevent malfunctioning of valves or pumps. The present invention also relates to a control system for operating a flush system.
In the course of manufacturing integrated circuits, it is typically desirable to selectively polish or planarize the surfaces of semiconductor wafers. Such mechanical treatment may be done to remove high topography, surface defects, scratches, roughness, or embedded particles. A chemical slurry may be used during such polishing to facilitate high removal rates and film selectivity. Polishing with slurry is sometimes called chemical-mechanical planarization (CMP).
Known CMP systems are illustrated in U.S. Pat. Nos. 5,679,169 (Gonzales et al.), 5,679,065 (Henderson), 5,658,183 (Sandhu et al.), 5,645,682 (Skrovan), 5,643,060 (Sandhu et al.), 5,514,245 (Doan et al.), and 5,314,843 (Yu et al.).
Slurries for use in CMP tools may contain small, abrasive particles and/or reactive chemicals. Conventional CMP slurries contain solutions of alumina or silica. Other slurries for integrated circuit (IC) manufacturing processes are mentioned in U.S. Pat. No. 5,664,990 (Adams et al.). Slurries tend to dry out, especially when they become stagnant or are exposed to air. Slurries may clog the conduits in polishing machinery and other manufacturing apparatuses. In addition, slurries can cause valves and pumps to stick or malfunction.